New Topic for the journal. Here I'll write notes for my paper
on a.i., which I will present at the Second Annual Enlightenment Meeting
this June.

First, some distinctions need to be made to keep things
clear.

There are several terms that tend to get confused in
discussions of dreams: 'REM sleep', 'brain wave pattern', and 'dream'.

REM sleep, or Rapid Eye Movement Sleep, is detected by looking at
the sleeping person's eyeballs rolling around under the eyelids. For the
purposes of this discussion, this is all that will be meant by REM
sleep--that the eyes are visibly rolling around.

NREM sleep, or
Non-Rapid Eye Movement Sleep, is detected by the absence of rolling
of eyeballs under closed eyelids. (In the OCM article on dreams, Iswald
says,
"There are two kinds of sleep..." Surely much finer distinctions are in order?)

Dreams are detected by asking conscious, non-sleeping people who have just awakened (or by their volunteering), generally in verbal form, "what were you dreaming?" or "what thoughts were passing through your mind?" The people then report, verbally, a dream. I sometimes refer to this as the subjective part of the experience, the qualia, if you will, of the neuronal activity.

IMPORTANT: People will report dreams when awakened during BOTH kinds of sleep. The difference is that, when awakened during REM sleep, people report more visually-descriptive dreams; when awakened during NREM sleep, they report less visually-descriptive dreams.

My Old Theory of Dreams (which I still believe, and now may have a good foundation for, in my New Theory of Intelligence)

We don't dream while we are asleep. Upon waking up, we confabulate: i.e., we tell a likely story that makes sense of the neuronal activity that had just been occurring. The origin of this theory is some information about pilots. When pilots stay up in the air for a long time, sleep-deprived and subjected to reduced air pressure, they report that they "saw" gremlins on the instrument panels. Sometimes the gremlins talk to them. Because the reports were so similar, coming from different pilots, the phenomenon was investigated. It was found that the capillaries in their eyeballs burst, causing some optic nerve stimulation but not in a way that the pilots could say they consciously saw. The conclusion was that, in order to make sense of this stimulus, they confabulated a story. Talked to Tom about this last week, who suggested that the reason that they pilots specifically reported seeing gremlins is that the term 'gremlin' has a long history in aviation. Anything that goes wrong in a plane is caused by "gremlins." Thus it would be a word in their ready-to-hand vocabulary, and some disturbance in their visual field could be interpreted as something "going wrong"--and since they were overtired (and possibly partly asleep), it wasn't all that surprising to them to actually start seeing the gremlins that were the source of all the problems. And this inspired me to suggest that, the human brain being set up to distinguish human faces better than pretty much anything, if the pilots had some visual sensation they couldn't immediately resolve in some other way, they might try to find a face in the blur. Gremlins. Completely confabulated in a more or less story-like way, on the basis of neuronal firing that couldn't be resolved.

This piece of information suggested that other bizarre phenomena might be similarly caused and explained. Thus, my theory of dreams, which recurred to me recently while I was drawing some diagrams in an attempt to understand and solve what Ted called "the binding problem in artificial intelligence". I'll detour here into my results, which didn't solve the binding problem (although it made me increasingly suspicious that it was a spurious problem akin to Xeno's Paradoxes), but produced a pretty little theory of how to save on processing and storage overhead when developing an artificial intelligence.

According to my developing theory of intelligence, we sleep in order to sort through and reorganize what we know. I refer, loosely and metaphorically, to what we know as "the big database."

Short-term memory is first in, last out: a stack. Like a can of Pringles Potato Chips, as Mike Young so handily put it when I was explaining stacks to him this weekend. Onto the stack, all day long, data gets pushed in the order in which it occurs: images, nice turns of phrase, people's names, faces--in fact, EVERY thing that we experience, whether we notice it consciously or not. Evidence that short-term memory can be usefully described this way, is this sort of example, which happens to people all the time: Suppose two people are having a long conversation. At some point they stop and say, "Wait a minute! What got us onto this? Weren't we talking about something else? Seem to remember it was important..." In general (and there are exceptions which I will consider separately, because I can use them to help explain the mid-term memory data structure)--in general, people find out how they got here in the conversation by literally retracing their steps, backward, thus:

"We started talking about libertarian politics because before that we were talking about Danielle Van Dam and how all of this could have been greatly alleviated if children had chips and transmitters implanted in their bodies and you started getting defensive about surveillance; and we got onto Danielle because I was half-watching the news while we talked, and, uh, before I got distracted by the news we were talking about, uh, Oh! Your ski trip, and the reason we were talking about that was that we were talking about the upcoming meeting and you were wondering whether you had the money to do both...

This kind of retracing seems to literally go in order: last in, first out. I'm popping the stack, trying to get to the bottom of the Pringles can so I can see where this conversation began. It is difficult--though not always impossible--to do it in another order.

The short-term memory stacks and queues are where we put stuff for temporary storage. These structures are not for understanding, but for brute storage. Later, we will empty them out element by element, and check it against the database for differences and similarities.

The big database is a multi-dimensional hash, or, as Ted O'Connor noted this week, it is not really a hash, but more of a soup. My understanding of a soup is that, like a hash, there are keys with associated data, but the structure is multi-directional. This avoids the wasteful problem of having a key refer to data that refers to the same key further down in the multi-dimensional hash. Instead, the data refers back to the key. I don't care how precise this is right now. I'm in a hurry, and there is much to be blurted out. My stacks are really, really full, my processors are working overtime, and I may even be asleep right now. I think I hear them coming to take me away....

Mid-term memory, which may come in several degrees or sizes or structures, is basically a temporary hash separate from the big database (where 'separate' might even mean, 'is one special flagged element of the big hash'). Recently, Ted and Jing Jing were here. Ted started some subject, Jing Jing asked a question about it. Though the subject was mostly unfamiliar to her, she suddenly said, "Oh! This is what Bernard was talking about." and then had something to say about what he said. Where was this stuff? It wasn't in short term memory; it didn't seem she was digging it out by popping a stack. Rather, she listen long enough until Ted said a key word or phrase--and it was a key she had in her mid-term memory hash. The data associated with that key was, in part, Bernard, and what he'd had to say about the topic.

Mid-term memory is where we are putting information that we need to access in a flash. Sometimes this is stuff we have already found places for in the big database, but we've pulled back out

Mid-term memory is where ALSO we are putting things, sometimes while learning them, that seem important but we don't yet know how to fit them into the big database--or perhaps even where we put things when we know how important they are but we're too tired to make a big, expensive query to the database (and we might say "I don't feel like talking about this (normally favorite) subject right now"). We forego brute efficiency of the stack and take on the higher space overhead of the hash in order to benefit from the random-accessibility of the hash. We can extract the information with lightening speed, even when we don't yet have a full understanding of it in the context of our wider knowledge. Perhaps the rule is even, "If it happened recently, it must be important." or "If it happened recently, then there's more information related to it that is sure to follow." Incidentally, this is another way of putting Price's classic theory of concepts as dispositions, where some concepts are just on the threshhold and ready to be used whereas others are buried more deeply and need more stimulation to be activated.

Let's look at some of the prejudices that are apparent in the article, simply stated without argument as basic fact.

The first sentence: "In our sleep we all intermittently experience insanity" (Dreaming, p. 201). This provocative sentence indicates that the author thinks there is no reasonable explanation of the bizarre things that we dream. I think that there is.

A couple of paragraphs later, Iswald says "We may need to dream, but no one has yet devised an experiment to see whether we have such psychological needs at night" (Dreaming, p. 202, col. 2). This statement indicates that, because the reported dream is considered a psychological phenomenon, the author's own thought processes are focused on the dream as psychological and important in and of itself, rather than as an effect of something that is important. I think it is an effect of something much more important.

Another strange statement regarding data: "While the majority of the REMs certainly cannot be ascribed to scanning the visual field of a dream-world, there are occasional large eye movements that do seem to bear a relation to described dream content" (Dreaming, p. 202, col .2). This statement suggest that Iswald is firmly in the camp that the actual _dream_ occurs during sleep, that the dream itself is the significant, interesting activity, and that the point of the neural activity and rapid eye movement is to cause the dream, rather than to do something important to us.

I think that dreams occur because we wake up and, being explainers and shelvers, need to make sense of the activity that had been occurring in our brains.

More on this article later.

Sleeping, Neuronal Activity, and Dreams

Popping the short-term memory stack and checking each element against the whole database is expensive, both in terms of processor overhead and time. Whatever else sleep may be for (healing, rebuilding, growing), this is when we are reexamining our information, finding fits, making connections, and storing. Studies indicate that we remember learned material much better if there is a period of sleep intervening between the time of learning and the time of testing. Why would this be so? If my emerging theory is correct, it is because we need to shut down all systems not directly essential to learn (or surviving), and focus all resources on going over the database, for a long, uninterrupted amount of time.

In large part, the bizarreness of dreams provides the inspiration for this emerging theory of intelligence. They give us some insight into how we're doing this thing called knowing. Consider the things you might store in any given day. Consider taking a single thing off the stack of things you stored, and checking it against the whole database. Suppose that I store the fact that Terry wants to go to the nursery to pick out the plants listed on my plan, on Saturday. I see him as he's telling me this, leaning over my patio gate. While sleeping, I get to this piece of data in my short-term memory stack, and check against everything I know. I'm somewhere in the medieval history portion of my database, when the alarm clock rings. I wake up with some disparate piece of data flying around in my head. I try to tell a story to make sense of it. So I say "I was just dreaming that Terry came over to tell me when we were going to the nursery--only I wasn't at my apartment. I was at the philosophy department at Indiana University. I was in Paul Spade's medieval logic class, and suddenly Terry just leaned in the window and started scheduling with me, and for some reason I didn't think this was strange at all...."

(previous in thread, caro) : ~ Studies ~ indicate that we remember learned material much better if there is ~ a period of sleep intervening between the time of learning and the ~ time of testing. Why would this be so? If my emerging theory is ~ correct, it is because we need to shut down all systems not ~ directly essential to learn (or surviving), and focus all resources ~ on going over the database, for a long, uninterrupted amount of ~ time. ~ ~ In large part, the bizarreness of dreams provides the inspiration ~ for this emerging theory of intelligence. They give us some insight ~ into how we're doing this thing called knowing.

In email, Brandyn introduced the issue of Long Term Potentiation (loosely, "the permanent strengthening of synapses which occurs in response to bursts of input activity happening just prior to the neuron firing,") and suggested an alternate explanation of why we seem to need to sleep after learning something:

Because LTP takes 8 to 12 hours to have an effect. The learning is triggered at the time of the event, but the results cannot be used until the physical changes have had time to take place. This is established to effective certainty.

This is useful information about the physical substrate. It's not fully integrated yet. Preliminary thoughts: While it is possible that those 8 to 12 hours needed for the physical changes to take place are usually happening while one is sleeping (the length of time is eerily coincidental, isn't it?), it is probably going on to some lesser extent while one is awake too. But it doesn't seem, offhand, that if I learn something in the morning then I'll be ready to use it by evening; more likely I'm ready the next day--a full 24 hours later, after I've had a night's sleep. So maybe the majority of this is happening during sleep.

But this is all very, very loose. Before getting too deeply into the discussion of how LTP is functioning, I'd want to establish what exactly is meant by 'learn', and by 'use'. For that I will need examples, of course. I need some article references.

Clearly, I do use some information as I'm learning it. A good example is a new step aerobics routine with new tricks with new names. There's only a minute to learn it and trying it; by the end of the class I'm supposed to have mastered it, and I could go home and teach it to a friend right away. It goes like this: At the beginning of the class, a new move is shown once, but we aren't shown the whole new choreography into which it fits--we're expected to listen closely and respond appropriately to increasingly complex sequences of commands. After we're shown the new move, we go on to the warmup and then to the beginning of the new routine. The new routine generally has moves in it we already know by name; they're just in a different order that we don't know ahead of time. Then, the leader reminds us of the move that we were shown at the beginning and expects us to do it in the middle of the rest of what we're doing. She deliberately makes up new moves that will stump us; she knows that's why we're coming back to her class, and that we'll complain if she doesn't do it.

Now, obviously, we're better at it the longer we do it. We are also better at it the next day. We get better at it if we visualize it between sessions. But nevertheless it does seem that we are using it right away.

Another example: An interactive programming class. The teacher shows us some new mind-boggling object. Then we do a couple of examples together, shouting out the next thing she needs to write on the board. Then we're turned loose at the terminals to write a little program to solve a problem using this new object. And we do it.

The contexts in which I've heard ordinary people talk about needing to sleep before taking a test are those where it is fairly clear that this material will NOT be memorizable in the hallway before the test. (Actually, some of us can pass a test with just-learned material, in a cheating sort of way, because we have a mental picture of it that we can then read during the test, but nevermind that for now.)

Here are some things that 'learn' could mean in the current context:

Learn: 1. Commit to permanent memory at least to the extent that we can talk about it later 2. Commit to permanent memory to the extent that using it becomes second nature, in the way that, say, using the plus-sign when we are asked to make a program add is second nature. 3. Get the general idea of. 4. Have a conceptual overview of. 5. Integrate deeply into one's full context of knowledge.

Use: 1. Regurgitate for the test. 2. Apply to new contexts without cues such as a test that is obviously dedicated to testing it. 3. Talk about it interestingly.

There are surely other senses of these terms that it would be useful to distinguish, and possibly use distinct words for.

I've had several days now to consider your explanation of dreams as risk-free practice. Brief overview: It doesn't seem prima facie unreasonable, but I do think it is too narrow (that just means that I think it fails to explain some typical and paradigmatic cases of reported dreams). I don't have an opinion yet as to whether it is true of at least some dreams; because it is so specific, I think it will take some time and effort form an opinion on that. However, I think it is compatible with the much more general theory I'm exploring. Let me re-read, and then discuss how....

...OK, I've re-read. In a moment I'll go out and deliver more brochures, and that will give me time to receive wide-ranging stimuli that will assist me in thinking about it. Here are my current thoughts.

First, I still don't want to talk about rat "dreams". I want to talk about what persons say when they wake up, and about what goes through my mind when I wake up.

Second, I need to try to think of actual dreams I've had that would fit the practice model. I am not sure this one fits, but it was a dream I had this week, after my conversation with Mike Young in which he offered the Pringles-can metaphor for a stack. Later that evening, I watched television show "The Guardian". In the story, a teenage girl was telling her child advocate that she and her younger sister didn't really have an address growing up, that they and their parents had lived in a mobile home, parked under a bridge. The next morning, I awoke and considered the following dream as I lay in bed: I "had been dreaming" that I was under a bridge, talking with some people in front of a table that had papers spread out on it. There was a mobile home in the background, also under the bridge. I had a bright red Pringles can in my hand, and I was explaining stacks to someone, I know not who or how many.

It is a challenge to see this dream as practice, unless by 'practice' we mean something much looser or broader than what I usually mean by it. Paradigm cases of practice, for me, are playing a harpsichord piece a couple of times trying to get the rhythm right; singing a difficult aria, in German, trying to do a better job each time to get the sequences of notes and foreign syllables right; repeating a new way of turning on rollerblades.

Less paradigmatic cases, which fall under a looser sense of 'practice' are, for me, deliberately getting into philosophical conversations with people who disagree with me so that I can find and be ready for new relevant objections. A lot less paradigmatic, to the point of overbroadening the concept PRACTICE, would be simply reading, watching television, talking, futzing with plants for no specific reason--in other words, practice as simply engaging in. Also, there is a sense of 'practice' that just means 'doing it or being that way'. It is in this sense that I say that engaging in _lying_ is a kind of practice, in that the more you do it, the more naturally it comes to you--more than mere habituation (which is just learning to tolerate, or something like that), but not exactly something that you're doing in order to get good at it, but you nevertheless get good at it by mere repetition in different cases.

Your case with rats can easily be interpreted as practice, for the obvious reason that you created it in order to show how dreams could be understood as practice. My case is less easily understood that way--not that it can't be, I'm just not seeing it. I feel like I have to leave a lot out of the dream on your explanation, that my explanation nicely encompasses. This doesn't tell me your view is wrong. It tells me it isn't enough. What is it that I am practicing, in this dream? Whether it's best to bring a Pringles can with me when explaining anything? When explaining stacks? That the can color matters (it is one of the most memorable and striking things about the dream)? Maybe it goes like this: Being under a bridge with a conference table full of papers in view of an RV and holding a food source is one scenario in which I might find myself explaining the philosophical background of the development of artificial intelligence. How did that go? Would it have been better to have been in the sun? Without the RV? Out of sight of distracting pieces of paper? In an actual conference room?

These are not rhetorical questions; I don't mean to imply by asking them that the answers are all "No!" It's possible that in fact the answers are all "Yes, these are factors which, during the rest of the night, I varied, and I was able to some degree to determine that explaining things to people inside of a classroom with a blackboard and desks for the students is in fact the best way to teach."

Another difficulty is what I am practicing in this dream. Explaining? Standing? Tolerating being in uncomfortable, visually unappealing places? Having the foresight to carry food sources around with me in case I find myself stuck under a bridge? All of these?

One answer to all of these difficulties is that I simply don't remember enough of the dream to make sense of it as practice. That answer is ok, I guess. But it does leave us with the difficulty of scant evidence. Some dreams are much more elaborate than this very sketchy one, but they don't necessarily lend themselves to interpretation via the practice model. For these, my model comes to the rescue. Would you be satisfied with that result? Or do you believe that the only explanation for why dreams exist is that they are simulations in which we practice, and thus every dream has a perhaps-inaccessible explanation in terms of practice?

A difficulty I would have with this requirement is that I tend to mix the most bizarre things in my dreams so that it seems extremely inefficient (in terms of speed, not in terms of aesthetics) compared to my own model of just going over the database to find likely fits.

Your model seems to focus on the question, "What if the world were like this?" In the case of the (fictional) rat's dream, the rat finds very relevant phantoms in his repeated resettings of the simulations: food smells, kitchens, cats, food rewards, hiding places that he knows. In my simulations, on the practice model, I encounter ever so many things that, given whatever you think is being practiced, are just irrelevant. Why would I need to practice those? Especially after almost 39 years of living on the Earth, I would think that I'd know better than to put unlikely things into my simulations. If it's a teaching simulation, say, you'd think I'd know better than to choose a dank shady underbridge with no place for the people to sit or even stand because there's a big RV in the way--maybe as a baby I'd consider that, but if all these years I've been practicing both while awake and in my sleep, wouldn't I by this time know better than to consider such silly things? Isn't that a huge waste of processing resources?

There's another dream I had recently. In reality, I had walked around the North side of Mount Soledad dropping brochures off at people's houses. I found one very large piece of ground with an empty house on it. I walked all around the house, feeling just a little out of place there but very curious to see if there was a chance that the owners were just away for the month and might be delighted to come back and find my brochure on the picnic table. The next morning, I awakened feeling like I'd dreamt about that house. There was a very deep, very steep "stairwell" that was most definitely not there on the real property. It was a sort of natural stair case made of roots and dirt. The stairs by the look of them seemed to be a navigable distance apart. As I bounded down them, the distances seemed to double, until I was flying down the staircase rather than bounding down it. Was I practicing going down stairs that change the distance between them as I traverse them? Or was I learning how to climb down a mountain that I had underestimated? If so why would I be doing that? Though I used to hike a fair amount, I haven't gone mountain climbing in probably two years; and while the terrain of La Jolla is hilly, I hardly need anything more than basic walking skills to navigate them, and I have those already. Was I preparing for the worst? For the big earthquake? I admit that this is a possibility. Maybe I'd got to the end of my stack, and now it was time to hang out admiring my database and making new connections, trying out new amusing things such as going to a stately home only to find that the "stairs" are really a huge dangerous vertical cave, and seeing what would happen if, in defiance of the laws of physics, I flew down it. I mean, why not? If I'm done with the rest of my processing, why not play?

My "grand" explanation at this point, which encompasses both our theories, is this: one of the many things that cause the subjective experience of dreams is the running of simulations to enable us to practice. But the subjective experience of dreams is also caused simply by waking up with a bunch of weird piece of data open because we happened to be in the middle of scanning the database. Those dreams can't be explained in terms of practice, and that's ok.

Perhaps, the more "sense" a dream makes, the more likely it is that we woke up in the middle of a practice simulation. But since the vast majority of reported dreams don't make as much sense as your rat-practice dream, I venture to suggest that practicing is only a small part of what we're doing while asleep. We're looking for connections in all sorts of ways, and one of them might be practice.

Another explanation that is less friendly to your practice theory might be this: We report dreams fairly selectively. Maybe we're just leaving out all the stuff that we can't tell a likely story about, and grasping at the few elements of which we can make sense, in just the way that commissurotomy victims do, and making up a likely story just about those. I think this is what my own experience of dreaming is like; I tell a story that's the best I can do, and just leave the stuff out that's too weird. This is illustrated also in the answer to your next question:

> I have a question-by-example for you that would help > me better understand your theory here. Take, for instance, > this: > http://interstice.com/journals/Simon/20001120.html> Can you elaborate what you think the actual process was > which created this memory upon waking?

I think so. Let's say at the point at which you got to the Church of Satan in the stack (which I seem to recall we were discussing right around that time, November 2000?), you were comparing it to some acrobatic images or moves or some figure skating stuff which were tucked away in your database. With evil sadistic charismatic people you also have some associated data such as religious showmanship, possibly the Steve Martin movie about same, supplying you with things like the wireless mic and the humor. It's hard to speculate without asking you more questions about what you know and what you've seen.

Let me try answering your question another way. Let's say that this had been my dream, not yours. Now let me explain it using my theory. I had been reading an essay on objectivism on the church of Satan site, before the dream happened. I'm scanning the rest of the database, and I come across the Cirque du Soleil data. Those two things seem similar, in that both are, to me, really dark (literally and figuratively), and weird, and mysterious in presentation, and intended to have a mystical quality about them. A kind of match. So I open up more of the details of the data about Cirque du Soleil: acrobatic, death-defying, rather bizarre stuff even when you're not dreaming. These performances happen on stage. What are some other things that happen on stage? The soup points out that church events happen on a kind of stage, and so do big university classes; in fact, when I teach, I feel like I'm giving a performance, and expect pretty much anything to "happen" (statements and questions from students are highly unpredictable and often bizarre): more similarlities. And universities figure big in my life, because I've done lots of good stuff and met lots of interesting people there. There are real possibilities for integration here! Let's load this whole chunk of circus and performance data into the temporary hash for further use somewhere else in the upcoming parts of the database.

Now I awaken. I've got three basic things in my hands: weird, dark, elaborate visual images of Cirque-du-Soleil-type acrobatics, (2) the Church of Satan (from the stack), and (3) stage performances broadly-construed. I awaken with a weird sense of all these elements being there togehter. And time being nothing but the distance between the ideas passing through the mind, as John Locke would have it, and the mere processing of the data probably having at least some sense of time associated with it, I immediately apply the dimension of time, lay the "events" out flat to the best of my ability on a time line. And that laying out "in time", maybe, is nothing more than listing the bits of data that I happened to have on my clipboard at the time, and lists having a temporal interpretation, I get a little story line that manages to make a bizarre kind of sense of data that really doesn't make any sense. Dreamatic license, we tend to give ourselves, and each other.

Now you try!

And I'll try your theory of practice: This dream is in some ways easier to see as practice than my Pringles can under the bridge dream. I am a physically active person. I also like to watch amazing feats of arial acrobatics. I'd like to investigate what it would take to do some of that stuff, safely. So I run a simulation that I can watch.

That's where the application of the practice model stops being easy. It's the Church of Satan and its minions that gets in my way here. Perhaps I wake up in the middle of simulation Number 50, which happens to check to see whether devil-worshipping would be helpful in developing acrobatic skill; I'd already run simulations that checked whether it would be better to be a rat, or a dove, or an objectivist, or a priest, or a space alien, or a software developer. Or maybe I just like to let devil-worshippers do all my stuntwork for me, as a sort of cosmic justice; and when I finally get a picture of the moves in my mind and I know it is safe, then I'll jump in and do it myself? Maybe the reason that I'm not doing the moves myself, is because learning by watching is a skill I need to practice too?

I feel like there are important aspects of the report that I have to leave out, in order to make it a practice simulation. Or else I leave them in, and find that I am, well, wasting valuable processing power and time by having weird irrelevant characters doing my simulations while shouting out quite strange and philosophical cues. Or maybe that's just for humor's sake? (Humor figures big in my intelligence theory, so I wouldn't be surprised by its coming in here.)

Responding to Carolyn on AI -- I hope this is getting published in the right place. Only have time to respond a bit right now, to the first entry (or the first bit of the entry, before the comments on the article).

(1) General question: Why think we can learn anything about how humans think from how we make computers do things that are similar to thinking? There are striking differences between what we do and what computers do. We perceive in order to get initial data. Computers get it from us typing stuff in -- and, if Searle is right, and I think he is, the information they get and process is only related to the world through us (computers exhibit only "derivative intentionality"). We *use* data to direct ourselves in the world as well as "process" it; indeed, these two functions would seem to be intimately interrelated. On the other hand, to the extent that we, in trying to build artificial intelligences of various kinds, are facing the same "engineering problems" that evolution did, we will certainly learn something about ourselves from AI. But what were the engineering problems evolution faced? Are they similar to those we face in creating AI? Of course, regardless of these general considerations, if there is sufficient similarity between the way we operate and the way our AI systems operate, it is worth pursuing. Conjecture and hypothesize away! I take it that these specific kinds of similarities are what motivate your view, and this is fine. But I think the general considerations such as the above are good to address as well.

(2) Why is the sleep-deprived state of pilots supposed to tell us anything about dream-states? Or is the idea that the pilot's state of mind is similar to our own when we are waking up (in which case the dream is similar to the visual neural stimulation caused by blood vessels in the pilots' eyes)?

(3) Why say that the pilots "make it up after the fact"? Maybe they really were having gremlin-experiences. In other words, this example does not seem to be a clear example of the "construction" or "confabulation" taking place after the fact.

(4) Why do we need to sort through the stacks later, when we sleep? We certainly integrate things into concepts and observe their relations as we perceive. Apparently, there is another kind of integration we need to perform that gets performed during sleep. What is it? (Side note: sorting through a stack is more like sorting through CDs in a juke box or flipping through pages in a book. The pringles analogy might suggest that, when we trace our way back through the stack following the chronology, that we actually take things off the stack (and eat them ;-)). But I take this is not the way this is supposed to go. The stack itself remains intact, but with "flip through" it. Correct?)

(5) I'm lost regarding the hashes and soups and keys? Waiter, there's a key in my soup!

(6) The units of information in our short-term memory stacks, on your view, would be perceptual memory-experiences, correct? But what are the units of information in "the big hash" or "big database"? Concepts? Propositions? Both? How do the elements interrelate? What is going on when elements of the big database are "compared" with the perceptual-memory units from the stacks? The language of similarity and difference suggests that the perceptual memory experiences are being subsumed under concepts (hence my earlier question). Is this what is happening? Are propositions being "stored" in concepts a la Rand's view of concepts as "file folders"? Are additional propositions being formed from perceptual memory data (additional concepts applied and relations recognized), so that they can be brought to bear on other propositions when we wake up?